I'm thinking hormonal changes. I'm on endometrin too and I've at times had a lot of creamy white d/c and at times quite at bit of clear watery d/c (other times not much at all comes out). I asked my RE about it early on (it actually happened with the gush of clear fluid for the 1st time during the 2ww and I was worried) and he said it was likely hormonal changes (which I'd guess are mostly d/t rising E2). I understand why you're so worried in general (I'm pretty constantly worried myself and I haven't even been through what you have) but my guess is that this isn't something to be too concerned about. Why not call your OB just to be sure? Sending good thoughts!